[cncwhiz]

I'm looking for some feedback on machining turned style parts on a CNC mill. I work for a company that makes our own product. We are an OEM for hydraulic elevator valves. We have 9 CNC machining centers. We do all of our milling parts. We have some idle machine time that I want to put to work by bringing some of our outsourced parts back from China. I have a few milled parts that are a no brainer. I however have some turned parts that I think that I can run on my machining centers. Has anybody used a boring head to cut on the outside? I worked at a shop years ago that had custom toos to do some end turning on crankshafts. I want to do the same thing. The bean counters are telling me that at this time, the old way that we manufactured these parts cost the same as they do making them in China. To me China is no longer an option which is great. Now I want to take the parts back and peoduce them at a lower price than China or the new China "mexico".

[littlerob]

I think depending on tolerance it is absolutely doable, some times I use an Endmill to helix around the O.D. of a part. But if they (the bean counters) can get it for a compirable price it's probably worth it. JMO. Robert

[keebler303]

How big are the pieces? If you could hold them in the spindle, you can mount a bunch of tools to the table and have a pseudo gang tool lathe. I have seen someone do it here on the zone, maybe a search would reveal it. Of course this is only applicable if you can chuck your parts in a collet or something in the spindle.

Matt

[Geof]

Provided the parts are short you can replicate a lot of lathe operations on a mill.

OD 'turning' can be done by interpolating around the outside; and this is where the length limitation comes in because the turned length has to be shorter than the milling cutter.

Threading is dead simple.

Grooves for O-rings or snap rings can be cut using slitting saws on long mandrels.

Show some pictures of what you would be making.

[cncwhiz]

I have heard of people using the spindle to hold the tool but I think that would limit the amount of work you can do in the same amount of time. Milling all the turned diameters is not a bad idea either but the lathe would kick you butt cycletime wise? I have horizontal CNC's with pallets. I am thinking about holding as many parts on my tombstone as I can fit. Then I can use boring tools to do all the turned diameters and chamfers. The rest of the part is drilling and tapping. I want as much up cycletime as I can produce. This allows my operator to work on other machines and not bust their butts loading parts all day.

[Geof]

Holding it on the tombstone is going to be a challenge isn't it?

Looking quickly at the picture I can't see how you can get away from at least one lathe operation to give you someplace for the subsequent fixturing to work from.

[cncwhiz]

I'm thinking about having our lathe shop turn the boss so I can us it to hold my parts. I will have to mill the face and rough the bore but the cycle time should be pretty short?

[Geof]

I'm thinking about having our lathe shop turn the boss so I can us it to hold my parts. I will have to mill the face and rough the bore but the cycle time should be pretty short?

The boss with the 3/4" internal thread? That would likely be the first operation I would do and then I would use this thread to fixture the part for mill operations.

[mactec54]

Hi cncwhiz

This is a easy part for mounting on your tombstone machine the large square end first with the taper sides holes etc then with the angle faces mount it in a vice jaw with the same angle cut in the jaw the angle will help to pull the part back into the vice then do the boss & thread no lathe operation needed no boring head needed (but you could use a boring head if needed for the bore)

[HuFlungDung]

Using a boring head for turning operations in the mill is going to be quite restrictive. A boring head is nothing more than a fixed point tool rotating at a certain diameter. Its orientation could be such that it can bore either a hole, or turn a single diameter OD boss.

Every different diameter requires a new boring head set to the appropriate diameter. Due to imbalance, it is likely an unworkable solution.

The instances I have seen of guys doing fancy profiles and fillets with the mill, they chucked the work in the spindle somehow, and then turned against a fixed tool held in a vise type fixture on the table. Even that can be a headache if the required G2's and G3's happen to turn out backwards to the normal machine motions.

[cncwhiz]

Did you look at the part pdf? I am only concerned with a few diameters, not a lot of profile work. For the production environment, its not too hard to "balance" a offset boring haed? I don't need to worry about "M3 & M4". I am the programmer as well as the tool designer.If you chuck the part in the spindle you might as well leave the part in China because you will not be the same or lower cost?

[LeftCoastCNC]

The only reason I can see you would want to use a boring head on this parts is if your machine will not hold the tolerances while interpolating or you need a better surface finish than you can get from an end mill... but I do not see any specs on the drawing that you can't hit with a decent mill.
If there is some other reason to use a boring head it seems like I read a while back about a CNC controlled unit but I can't remember who makes it. Criterion makes a head that will change diameter when it hits a mechanical stop for o-ring grooves and undercuts-- it is designed to use in a CNC mill. I have no experience with them other than knowing about the technology.

[cncwhiz]

Its all about cycle time? If I use an endmill, I can't compete with a lathe? I need to have a lower price than China?

[HuFlungDung]

Did you look at the part pdf? I am only concerned with a few diameters, not a lot of profile work. For the production environment, its not too hard to "balance" a offset boring haed? I don't need to worry about "M3 & M4". I am the programmer as well as the tool designer.If you chuck the part in the spindle you might as well leave the part in China because you will not be the same or lower cost?

Indeed, I did look at the pdf, twice now

I don't see anything that you can do on the outside of that part with a boring head: you cannot turn a taper, nor form external fillets, or do multi-pass OD turning without calling a new boring head for every cut. It just doesn't look like a job for boring heads to do OD turning on a mill at all.

[cncwhiz]

I am thinking about having the boss on the top of the part turned before I get it? If I give the whole part to the lathe shop, they will have two lathe setups and three mill setups. If I have them turn the top boss then I can do the rest in two setups on the same machine. Pallet A and B will hold the part in the same way but with the part turned on the boss 90'. I can rough the stock with a mill in the cavity and do the finish work with boring tools. I might try to get away with not rough milling? I can then do all of the drilling and tapping except for one hole. I might try to split up some of the work so the operator can attempt to keep up with the loading?

[NIL8r]

["I don't see anything that you can do on the outside of that part with a boring head: you cannot turn a taper, nor form external fillets, or do multi-pass OD turning without calling a new boring head for every cut. It just doesn't look like a job for boring heads to do OD turning on a mill at all. "]

How 'bout a programable u-axis/boring head?
http://www.kometgroup.com/pdf/infos/0193230.pdf

[PixMan]

While a CNC lathe would be lower cost initially, that part is very doable on a CNC machining center if set up for big volumes. The reason I say big volumes is because the cost for feed-out boring heads and other special tools is going to take a lot of parts to amortize the cost.

Valenite's Modco division has long supplied special tooling for difficult parts like that for the automotive industry, and could quote you for tools to make that part efficiently. Expect a big burn hole in the wallet, however. They make custom tooling similar to that U-axis tool posted below.